The Influence of Tile Drainage Spacing on Water-Table Fluctuation and Alfalfa Crop Production in the Northeast Nile Delta, Egypt

Low-lying areas, heavy clay soils with little permeability, saline and saline-sodic soils, and shallow and saline groundwater are all problems in Egypt’s northeast. An experimental field was established on heavy clay soil in the northeastern Delta (Damietta Governorate) to compared the effects of different tile drainage spacings on groundwater level decline, productivity increase and soil degradation prevention over three growing seasons. The experiment was designed as a complete block randomization with four replications. The treatments consisted of three tile drainage spacings, as follow: 15m (T4), 30m (T3) and 60m (T2) at a depth of 1.5 m fixed, separated by buffer zones. There was no tile drain treatment (T1) used, and the crop grown was alfalfa. In the four cuts, fresh and dry alfalfa yield weights, root volume, and fresh and dry root weights increased with subsurface drain compared to control treatment, as increased with decreasing the drainage spacings. The drain spacings also, had an effect on the water table depths in the following order: T4 > T3 T2 > T1. T4 is the best three seasons treatment for lower water table. In all treatments, the soil salinity in the upper surface layer is lower than in the deeper layers but the soil salinity decreased significantly with the reduced spacing tile drain. Finally, narrow tile drainage spacing provided a better cropping environment with faster water-table drop, lower water-table depths, and lower soil salinity